Hello,
i am working on a section of a project, that uses large number of sum methods.
These sum methods are applied on a Datatable
To test the best method, i use the following
Datatable structure
Class ParseLog
{
public DataTable PGLStat_Table = new DataTable();
public LogParser()
{
PGLStat_Table.Columns.Add("type", typeof(string));
PGLStat_Table.Columns.Add("desc", typeof(string));
PGLStat_Table.Columns.Add("count", typeof(int));
PGLStat_Table.Columns.Add("duration", typeof(decimal));
PGLStat_Table.Columns.Add("cper", typeof(decimal));
PGLStat_Table.Columns.Add("dper", typeof(decimal));
PGLStat_Table.Columns.Add("occurancedata", typeof(string));
}
}
Following method is used to Fill the table
LogParser pglp = new LogParser();
Random r2 = new Random();
for (int i = 1; i < 1000000; i++)
{
int c2 = r2.Next(1, 1000);
pglp.PGLStat_Table.Rows.Add("Type" + i.ToString(), "desc" + i , c2, 0, 0, 0, " ");
}
- Sum is applied on count column, where value of c2 is updated
Following Methods used to calculate Sum
Method 1 using Compute
Stopwatch s2 = new Stopwatch();
s2.Start();
object sumObject;
sumObject = pglp.PGLStat_Table.Compute("Sum(count)", " ");
s2.Stop();
long d1 = s2.ElapsedMilliseconds;
Method 2 using Foreach loop
s2.Restart();
int totalcount = 0;
foreach (DataRow dr in pglp.PGLStat_Table.Rows)
{
int c = Convert.ToInt32(dr["count"].ToString());
totalcount = totalcount + c;
}
s2.Stop();
long d2 = s2.ElapsedMilliseconds;
Method 3 using Linq
s2.Restart();
var sum = pglp.PGLStat_Table.AsEnumerable().Sum(x => x.Field<int>("count"));
MessageBox.Show(sum.ToString());
s2.Stop();
long d3 = s2.ElapsedMilliseconds;
After Comparison the results are
a) foreach is the fastest 481ms
b) next is linq 1016ms
c) and then Compute 2253ms
Query 1
I accidentally change "c2 to i" in the following statement
pglp.PGLStat_Table.Rows.Add("Type" + i.ToString(), "desc" + i , i, 0, 0, 0, " ");
The Linq statement produces an Error "Arithmetic operation resulted in an overflow."
Whereas the Compute and Foreach loop are still able to complete the computation
Is such a behaviour cause of concern or am i missing a directive ?
(also the figures computed are large)
Query 2
I was under the impression Linq does it fastest, is there a optimized method or parameter
that makes it perform better.
thanks for advice
arvind
